Leigh Van Valen : biography

Leigh Maiorana Van Valen (August 12, 1935 – October 16, 2010) was an American evolutionary biologist. He was professor emeritus in the Department of Ecology and Evolution at the University of Chicago.

Amongst other work, Van Valen's proposed "Law of Extinction" drew upon the apparent constant probability (as opposed to rate) of extinction in families of related organisms, based on data compiled from existing literature on the duration of tens of thousands of genera throughout the fossil record. Van Valen proposed the Red Queen Hypothesis (1973), as an explanatory tangent to the Law of Extinction. The Red Queen Hypothesis captures the idea that there is a constant 'arms race' between co-evolving species. Its name is a reference to the Red Queen's race in Lewis Carroll's Alice Through the Looking Glass, in which the chess board moves such that Alice must continue running just to stay in the same place.

Van Valen also defined the Ecological Species Concept in 1976, in contrast to Ernst Mayr's Biological Species Concept. In 1991, he proposed that HeLa cells be defined as a new species, which was named Helacyton gartleri.

Van Valen originated the concept of fuzzy sets, prior to the formalization of this concept by L.A. Zadeh .

He had deep understanding of many fields outside of biology, including measure theory, probability theory, logic, thermodynamics, epistemology and the philosophy of science. It is widely thought that the unusual breadth and depth of his knowledge contributed to his great originality in the field of biology and elsewhere. On the same time, Van Valen as biologist considered the role of the zoological and botanical gardens, in a world where the natural environment is degraded more and more, essential for the safeguard of the endangered flora and the fauna.

Biography

He was born in Albany, New York. He earned a zoology and botany degree at age 20 in 1955 from faculty of biology at Miami University in Ohio. He attended Columbia University and studied under George Gaylord Simpson and Theodosius Dobzhansky.

Van Valen married Phebe May Hoff, but they divorced in 1984.

He died on October 16, 2010 of pneumonia at St. Mary of Nazareth Hospital Center in Chicago, Illinois. Van Valen had been hospitalized for more than three months from a rare form of slowly progressing leukemia.